The scope will be offered as both a TL and an LE. All options available on the LE Series will be the same. However, the TL will be available as a “push to” only, no goto option. All other listed options on the TL will be available. The Horizon for both series has been fully tested and ready for production.

There will be no price increase to the LE Series and just a small increase to the TL Series. All details will be on the web site soon.

Hi Gene,Pretty much just what I stated...The TL Series Horizon will be for those that are just looking for a basic scope. No Goto System. But you can get A DSC, secondary dew heater, balance weight kits, etc.

Thanks Paul,
In the case of the Horizon…bigger doesn’t necessarily mean bigger.

The Horizon sizes are running a full size smaller then the standard LE design. (RE: An 18" scope is the same size in the square dim as the 16" a 20" same as the 18" etc...) Consider that my LE scopes are already smaller then most other designs. When we include the 2.5” added for the Servocat altitude drive motor that now installs under the mirror box the Horizons are running 5.5" less in width.

Altitude bearing heights are running about 8" to 14" lower (depending on size) when in transport mode.

The 16" prototype scope has a 21" height when in transport mode.
The standard 16" LE is about 29.5"+ depending on focal length.

The design really shines on the big boys. With 22” and up you really see the difference.

Anyone considering a 40” plus dob...this bad boy is DEFINITELY for you !!!!

Photo showing the 16" prototype scope before finishing.

Mike Z

Attached Files

One of the potential disadvantages of using struts of unequal length is that collimation changes as a function of temperature. The amount of mis-collimation depends on many variables such as the lengths and length differences of the struts, their coefficients of thermal expansion, the temperature change from when the telescope was collimated, etc. Whether the magnitude of mis-collimation is an issue depends on the allowed tolerances for differant focal ratios, among other things. Have you determined the mis-collimation vs. temperature for the various telescope sizes?

Great question, I certainly expected the design to get pulled apart here on CN.

To answer your question...No I have not tested every size because I don’t see it as a problem.

It’s important to understand that the back 4 trusses (long ones) are all the same length. Same as the front 4 (short ones)

From the smallest scope to the largest, there is from an 8” to 30” differential in length.

Considering the largest 30” differential in length using a 6063 T52- 2” OD pipe with a .055 wall and using a 30 degree temperature shift over a 6 hour period (basically 5 degree +/- per hour shift) Using a .000023 coefficient (m/m* c) I see a length shift of about .002. This and how it would equate to actual secondary misalignment to the primary is probably a quarter of that as most of the expansion would be absorbed in the attachment points of the trusses.

The biggest factor (which makes the math almost impossible to calculate) is the inconsistency of the alloy throughout a given pipe. Another words...you will be hard pressed to find 2 equal length pipes cut from the same piece that will expand at EXACTLY the same rate. I know this for a fact with my over 30 years of welding experience that there are hard and soft spots throughout extruded aluminums.

Because “tweaking” collimation during the night, on a Dob, should be looked at as common practice rather then an inconvenience. And when considering expansion and contraction throughout the entire structure of a Dob (which is far greater then any you’ll see in a few inches of length difference in these trusses) This is a none issue.

Thanks,

Mike Z

PS...Quick note, all the trusses on the Horizon are rubber wrapped, so the temperature of the trusses will be very stable.

Hi Mike,I really like the new design. It is awesome that you are always looking for new and better ways to improve something that is already top notch. Does the servo-cat still have to be used with the cable? I've always hated to have to set up the cable at night.Maykel

Great question, I certainly expected the design to get pulled apart here on CN.

Hi Mike,I'm not trying to pull it apart. Just want to point out a potential issue. Some customers may be reluctant to buy a telescope where mis-collimation as a function of temperature is introduced by design. I belong to the school of thought that if you can't see it, it doesn't matter. So I believe in tackling the issue head-on.

To answer your question...No I have not tested every size because I don’t see it as a problem.

You don't necessarily need to test every one. I derived and experimentally verified equations that address this case as well as many others. You can calculate the expected deviations vs. temperature.

It’s important to understand that the back 4 trusses (long ones) are all the same length. Same as the front 4 (short ones)

This insures that no mis-collimation is introduced side-to-side. But there are two consequences of the set of longer and shorter struts.

Considering the largest 30” differential in length using a 6063 T52- 2” OD pipe with a .055 wall and using a 30 degree temperature shift over a 6 hour period (basically 5 degree +/- per hour shift) Using a .000023 coefficient (m/m* c) I see a length shift of about .002. This and how it would equate to actual secondary misalignment to the primary is probably a quarter of that as most of the expansion would be absorbed in the attachment points of the trusses.

I'm not sure what the 0.002 refers to since it appears without units and you mixed units in the paragraph. For a 30" difference, I calculate a change of approximately 0.01" over a 30 F temperature change. This introduces a rotation of the upper optical assembly. I don't know your dimensions, but I estimate that the rotation is less than one arc min. I don't think this is an issue for most folks.

A potentionally larger issue is one you didn't address. The change in length between the struts in the two side trusses is magnified by the ratio of strut length divided by their base separation (actually, the separation measured perpendicular to the telescope optical axis). The equation becomes a little more complicated since the the struts are of unequal length, but the mis-collimation is easily calculated. The mis-collimation is front-to-back. Again, I don't know the dimensions of your telescopes, but I estimate the amount to be approximately 0.02". Again, I doubt few could detect this. Some truss telescopes show greater deflection between vertical and horizontal and their owners don't seem to notice or care. Others might since the magnitude is larger than stiff truss structures show when traversing the same angular orientations.

PS...Quick note, all the trusses on the Horizon are rubber wrapped, so the temperature of the trusses will be very stable.

No doubt the rubber will cause the temperature of the struts to lag, but I'd wager that at any point their temperature is closer to ambient than they are to the initial temperature. Of course, no need to debate. Easy enough to measure.

Hi Pinbout,No tail gate. The primary will be installed and removed from the top of the mirror box. I have designed the scope so that the top plate of the mirror box is removable so there is plenty of room to get to it. The scope shown was the concept scope and it does have a rear opening. On the final design the opening is much bigger. I also designed in side ventilation as well.

Albert,
First, let me apologize for that first sentence, it was a joke. I should have included a LOL...

I respect what your saying , I really do, but I have to submit that your not familiar with the way the scope assembles. My problem with your math is that you are taking your equations and applying the movement directly to the UTA, this is simply not the case. As I stated, the majority of this differential between trusses will be absorbed in the attachment points of the trusses.

For example...on the upper attachment points we have two trusses that mount to a triangular plate to complete the connection to the UTA.

During fabrication, the trusses are bolted to the plate and then install on the scope. Once the upper plate is aligned correctly the bolts are tightened and the trusses are removed. Next I weld ONE of the trusses to the plate which holds the plate at the correct angle when installed on the scope. The other truss is mounted in the following order: Bolt / SS flat washer / triangle plate / nylon washer / truss / SS washer / locknut. The locknut is tightened to a point that allows the truss to collapsed for transport. In this attachment there is probably .003” to .005” amount of play. This would also hold true for the lower attachment points, at the mirror box, which are installed on the scope in a similar way.

So right here...before this differential is going to put LOAD (and lets be clear that the UTA and mirror box assemblies are very rigid pieces) on the UTA / mirror box, there is going to an allowable movement at these connection points that will have a minimal effect on UTA orientation.

I want to be clear, when the scope is assembled and NEUTRAL there is no noticeable movement, but before a length differential in trusses as a result of temperature change is going to actually TWIST the UTA assemble, (a result of direct LOAD) these points will give first.

I think the most important statement you made was that most (if any) will even notice on a visual instrument.

If this was an imaging scope well then your comments would definitely have merit.

One more point I would like to submit, is that the example we are giving here is on the extreme end.

I'm trying to hire someone to build me a pro site, so this may be a little while. I do have all the specs and pricing for all sizes from 8" to 30" ready to go. If anyone wants info on a specific size just drop me an e-mail. Please be patient with me as I’m being hammered with e-mails. I may take a few days to get back with you.

I'm trying to hire someone to build me a pro site, so this may be a little while. I do have all the specs and pricing for all sizes from 8" to 30" ready to go. If anyone wants info on a specific size just drop me an e-mail. Please be patient with me as I’m being hammered with e-mails. I may take a few days to get back with you.

Mike, As you know by now, there are some diehard scope owners from other brands that are just mesmerized by your new Horizon telescope. They told me this afternoon that they have been calling you and figuring out ways to get one of your new scopes into their arsenals. What a fun problem to have. Bob